CI: test dmd and ldc2 on ubuntu macos and windows

Signed-off-by: Andrei Horodniceanu <a.horodniceanu@proton.me>

.github/workflows/d.yml

@@ -15,20 +15,26 @@ permissions:
 
 jobs:
   build:
-
-    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        dc: [dmd, ldc]
+    runs-on: ${{ matrix.os }}
 
     steps:
-    - uses: actions/checkout@v4
-    - uses: dlang-community/setup-dlang@v2
+      - uses: actions/checkout@v4
+      - uses: dlang-community/setup-dlang@v2
+        with:
+          compiler: ${{ matrix.dc }}
 
-    - name: 'Build & Test'
-      run: |
-        # Build the project, with its main file included, without unittests
-        dub build
-        # Build and run tests, as defined by `unittest` configuration
-        # In this mode, `mainSourceFile` is excluded and `version (unittest)` are included
-        # See https://dub.pm/package-format-json.html#configurations
-        dub test
-        # Run tests
-        cd tests && rdmd test
+      - name: 'Build & Test'
+        run: |
+          # Build the project, with its main file included, without unittests
+          dub build
+          # Build and run tests, as defined by `unittest` configuration
+          # In this mode, `mainSourceFile` is excluded and `version (unittest)` are included
+          # See https://dub.pm/package-format-json.html#configurations
+          dub test
+          # Run tests
+          cd tests && rdmd test